Chinese traditional medicines are traditionally used in China, and there is a historically long time in China using Chinese traditional medicines to treat patients. The World Health Organization also recommends using Chinese traditional medicines, thus with the hope that people can get the Chinese traditional medicines with safety, high efficiency, speed and convenience. However, because the production processes of Chinese traditional medicines, especially the extraction and separation drop behind relatively, it is hard to achieve the standardization and criterion of the quality control. It is always difficult to register, sell and use Chinese traditional medicines legally in the world market.
In recent years, the modern equipments such as stainless steel multi-functional cans, external-circulating vaporization, multi-purpose vaporizer, fluid dryer etc. are used in the traditional production of Chinese traditional medicines. There is also some progress in the preparation of Chinese traditional medicines, such as the preparations of granule, tablet, capsule and oral solution. However, in general, the extraction process of Chinese traditional medicines is substantially still “All-In-One-Container” decocting, or rough extracting using water and ethanol under high temperatures (above 95° C.) (i.e. “water extracting” or “alcohol extracting”), or the additional low temperature drying and super fine combination. There are many disadvantages with the prior arts. This kind of Chinese traditional medicines production method, lacking the scientific and strict processing manipulation parameters, is of high energy consumption and low efficiency. Because high temperature is necessary for extracting, parts of the active substance in the medicine are destroyed, only partial effective component is extracted, and the rest of effective component are destroyed, lost and abandoned as remaining in the residua during the course of production. This affects the extracting ratio of Chinese traditional medicines, causes environmental pollution, leads to the instability of curative effect, the bad taste and color of the production and the internally instability in quality, among other things. Thus, in the course of research development and industrialization, the technology of Supercritical Fluid Extraction occurred, especially the new technology used in the aspect of medicine extraction and purification. The course of supercritical fluid dissolving and extracting the substance is named as Supercritical Fluid Extraction (with the abbreviation of SFE hereinafter). Generally, CO2 is preferably used in supercritical extraction, and the basic principle is that the critical temperature (Tc) of CO2 is 31.05° C., and the critical pressure (Pc) of CO2 is 7.98 MPa, and when they are over critical point, CO2 will exhibit the dual characters of a gas and a liquid. It is similar to a gas in its viscosity, and it is similar to liquid in its density. It is an excellent solvent which will dissolve many substances through the interaction and diffusion within the molecules. Meanwhile, in the range slightly above the critical point, the slight change in pressure will cause notable change in the density; thereby the solubility will change greatly. The supercritical CO2 may dissolve the substance out from the medium, thus forming the supercritical CO2 loading phase, and reduce the pressure or increase the temperature-so the solubility of supercritical CO2 will reduce. These substances will precipitate out to separate from the CO2, thereby achieving the target of extracting and separation. Because different substances will have different solubility in CO2, and even the same substance will have different solubility under different pressure and temperature, this makes the extraction method have relatively high selectivity.
However, supercritical CO2 extraction also has disadvantages hard to overcome. First, the cost of such extraction method is relatively high. Because CO2 works under the supercritical situation, it is necessary to use high-powered air compressors to carry out the compressing cycle to the CO2 gas. This will last the whole process of extraction, and results in high electric power consumption and high cost. Second, gases always are dangerous under high pressure, which causes the problem of manipulation safety. Third, the solubility of supercritical CO2 is not as big as the liquid solubility, which makes the production efficiency relatively low. Finally, supercritical critical extraction is more suitable for the extraction of single component, but can not ensure the extraction of wholly single component, so it is not suitable for the extraction of full-components from Chinese traditional medicine or plants.
In recent investigation of the effective components of Chinese traditional medicine and the related plants, it is found that the rough extracts from these Chinese traditional medicines are much better than a pure component in the aspects of bioactivity and less toxicity. For example, Japanese researcher Akihiko Satou et al., in the course of using the Hela cancer cell to select the activity of anticancer of Chinese traditional medicine, found that some types of extraction with the activity of anticancer will have higher activity and higher toxicity when the purity is higher, while another type of extraction with very high activity and no toxicity, will have lower activity when the purity is higher. Another example is the extraction of devil-pepper, which will have no adverse effects such as depression as caused by Reserpine when used for a long time. All of the above samples demonstrate that a bioactive guide is obtained through the cooperation of many components with each other. Thus, the traditional extracting methods under high temperature, whether using water or alcohol, will always partially destroy original active substances in the medicines, and may cause the generation of some toxic adverse effects. However, the technology of supercritical extraction cannot ensure extracting a pure single component or carrying out the extraction of full-components.
Based on the above description, considering the severe backwardness and deficiency existing in the technology of extracting effective functional components from Chinese traditional medicine or related plants, it will have important theoretic and practical significance, in the aspect of extracting the substantial full-components from Chinese traditional medicine, plants or other material, to investigate and develop a new method protecting the effective components in the Chinese traditional medicine and plants from being lost and destroyed, which will also ensure the extraction of substantial full-components.